Abstract: A compact, integrated intravenous fluid delivery device. In one embodiment, the invention may be used with first and second intravenous fluid sources and an intravenous fluid line. This embodiment includes a spike for connecting the device to the first intravenous fluid source. A fluid passageway passes through the spike. A connection site (e.g. a puncture site) connects the device to the second intravenous fluid source. This embodiment also includes a drip chamber, through which the fluid may flow to the intravenous fluid line. This embodiment may include an adjustable valve, which includes a flexible tube mounted so that fluid may pass from the fluid passageway in the spike, from the connection site, and through the tube. The valve includes an actuator mounted with respect to the tube so that it may be urged to compress the tube. The spike, the adjustable valve, and the drip chamber are rigidly attached to each other, with no flexible tubing between the various components.

Abstract: A system for controlling the flow of fluid through a line (3). The system may include first and second valves (A, B; and 6, 7) in the line (3). Between the first and second valves is located a chamber (52, 82), part of which may be filled with fluid having a variable volume (52), and another part of which is filled with a measurement gas (82, V.sub.1), such as air. The chamber may be isolated from the pressure effects in the rest of the line by closing both valves. The valves may also permit fluid to flow into or out of the chamber. The second portion of the chamber has a common boundary with the first part in such a way that the combined volume of the first and second parts is constant. A loudspeaker (22, 33, 571) creates sound waves in the gas in the second part of the chamber, in order to measure the volume of the fluid in the first part.

Abstract: A valve for controlling intravenous fluid includes a flexible membrane (11), which together with a rigid body (21) forms a valving chamber (29). Two mouths (27, 32) lead into and out of the valving chamber. In one embodiment, a stem (23) having an enlarged portion (15) is attached to the membrane's inner face and extends into the outlet mouth. Fluid pressure on the inner face causes the enlarged portion of the stem to press against a narrower portion (38) of the outlet conduit, thereby preventing flow through the outlet conduit. External pressure on the membrane's outer face causes the enlarged portion of the stem to separate from the outlet conduit's walls, thereby permitting flow through the outlet conduit. In another embodiment, a groove (43) is placed near one of the mouths. The membrane may be pressed against the rigid body and the groove, so as to prevent flow except through the groove and to variably restrict flow through the groove.

Abstract: A compact intravenous fluid delivery system for intravenous injection of fluid into a patient has in one embodiment a spike, for connection to a fluid supply reservoir whose top and bottom define a vertical interval; a fluid metering device for accepting fluid from the reservoir and for displaying the flow of fluid; a fluid cannula for conveying fluid from the spike to the fluid metering device: a fluid delivery tube for conveying the fluid from the metering device to the patient; and a reservoir mounting frame for mounting the fluid supply reservoir in relation to the metering device so that the metering device is substantially contained within the vertical interval defined by the top and bottom of the reservoir. In a preferred embodiment, an intravenous tube having a length greater than 20 cm provides a conduit for passage of fluid from the fluid reservoir to the metering device.

Abstract: An air elimination system is provided for an intravenous fluid delivery system for intravenous injection of fluid into a patient. An air-detection apparatus (5) is disposed in an intravenous fluid line (3). A return line (8) is attached to a point in the line (3) below the air-detection apparatus (5). The other end of the return line (8) is attached to a chamber (1, 2, 12) where air may be separated from the fluid. The separation chamber may be a drip chamber (12), a metering chamber (2) or the intravenous supply (1). When air is detected, a valve (11) or valves (7, 9) are switched, so that the intravenous fluid is prevented from flowing to the patient, and so that, when a pump (4) is turned on, the fluid is pumped through the return line (8) to the separation chamber (1, 2, 12).

Abstract: A compact, integrated intravenous fluid delivery device. The invention may be used between an intravenous fluid source and an intravenous fluid line. In this embodiment, the invention includes a housing, through which a fluid passageway is disposed. The fluid passageway passes through a spike, which is used for connecting the housing to the fluid source. The passageway also passes through a rigid drip chamber and a priming element that may be repeatedly compressed in order to urge fluid from the source into the drip chamber and through the intravenous fluid line. The priming element includes a rigid base portion and a membrane. The spike, drip chamber and the base of the priming element all form an integral piece of rigid material. This embodiment may further include a valve chamber disposed in the housing, such that the fluid passageway enters and exits the chamber through two mouths.

Abstract: A system that permits highly accurate flow control, even at very low flow rates, by providing a measurement chamber and an auxiliary dispensing chamber having a volume that is variable between fixed maximum and minimum limits. The maximum volume of the dispensing chamber is substantially smaller than the maximum volume of the measurement chamber used in this type of system. The dispensing chamber can then be filled to its maximum volume from the measurement chamber and thereafter caused to be reduced over time to its minimum volume. Because the maximum and minimum volumes of the dispensing chamber are known, the volume change of the dispensing chamber per unit time is determinable and is the flow rate out of the system.

Abstract: A valve having a disposable portion, which comes into contact with the fluid being controlled by the valve. The disposable portion has a valving chamber and a flexible membrane, which can seal off a mouth that is located on a protrusion in the chamber. The disposable portion is held by a fixture which uses a control gas or a mechanical actuator to apply pressure to the flexible membrane. The disposable portion may also have a pressure conduction chamber, which may be used to measure the flow rate of liquid through the disposable portion.

Abstract: A normally-closed valve that can be easily connected and disconnected. Disposed in the fluid passageway through the valve is a flexible, resilient disk and a pin mounted adjacent to the disk. The disk is mounted in a wide portion of the passageway and is held in place by the narrow portions of the passageway. The disk fits snugly into the passageway so that the edge of the disk forms a seal with the wall of the passageway. A nozzle is inserted into the passageway and urges the pin against the disk, causing the disk to deform. When the disk deforms, its effective diameter decreases, and its edge separates from the passageway wall, permitting fluid to flow through the valve. The narrow sections of the passageway wall have channels disposed therein for permitting flow when the disk is deformed. The pin also has channels on its surface to permit flow around it.

Abstract: A valve having a disposable portion, which comes into contact with the fluid being controlled by the valve. The disposable portion has a valving chamber and a flexible membrane, which can seal off a mouth that is located on a protrusion in the chamber. The disposable portion is held by a fixture which uses a control gas to apply pressure to the flexible membrane. The disposable portion may also have a pressure conduction chamber, which may be used to measure the flow rate of liquid through the disposable portion.

Abstract: A system is provided for the automatic, self-checking switching of a medical infusion controller among a plurality of modes of operation. A medical infusion controller has a plurality of pressure-sensitive switches, each of which corresponds to a different mode of operation. A drip chamber is provided with nub elements in one of a variety of possible configurations, each of which correspond to one of the pressure-sensitive switches on the controller. When the drip chamber is placed in the controller, the nub configuration activates the corresponding switch. If the controller detects an incorrect number of nubs, it delivers an error message.

Abstract: A system for measuring flow of fluid through a line. A portion of the fluid in the line is isolated in a rigid container so that the fluid in the container is not affected by pressure in the rest of the line. An apparatus is provided for measuring that portion of the container that is not occupied by the fluid. In order to urge fluid into and out of the container, a positive pressure source, for providing gas to the container, and a negative pressure source for removing gas from the container, are provided for.

Abstract: The present invention provides a system for measuring flow of a fluid through a line. In the system, a region of fluid along the line is isolated from pressure effects outside of the region. A source region contains a measurement gas in communication with the isolated region, such that the source means and the isolated region together define a fixed volume, and such that a change in volume of fluid in the isolated region produces a complementary change in the volume of the source means with a resulting change in the pressure of the measurement gas contained in the source region. Further provided is a reservoir in communication with the source means for containing a known volume of measurement gas, and means for pumping measurement gas from the reservoir. The pressure of the measurement gas in the reservoir and the source region is monitored. This pressure data is then analyzed to determine the volume of fluid in the isolated region.

Abstract: A system is provided for detecting the presence of an infiltration condition in a line delivering fluid to a patient. Stepping means subjects the fluid in the line to a negative pressure step. The pressure of the fluid is monitored, and processing means then determines whether an infiltration condition is present by determining whether the function of line pressure over time in response to the occurrence of a negative pressure step exhibits a relative slow return to the pre-step pressure, such relatively slow return being characteristic of the presence of infiltration.

Abstract: A system is provided for controlling flow of a first fluid through a line. Dispensing means isolates a region of the first fluid in the line from effects of pressure in the line outside of the region and repetitively dispenses into and out of the region volume increments of first fluid. Measurement fluid housing means houses measurement fluid in communication with the region such that the dispensing of increments of first fluid into or out of the region causes a change in the measurement fluid pressure. Displacement means displaces a predetermined volume increment of measurement fluid into and out of the measurement fluid housing means, such that displacement of the predetermined volume increment causes a change in the measurement fluid pressure when the region is isolated by the dispensing means. Pressure measurement means measures changes in measurement fluid pressure.

Abstract: The invention provides an intravenous line valving system. The invention includes a flexible tube mounted onto the interior surface of a drip chamber spike, the spike having an aperture through its exterior. A preferred embodiment of the invention includes squeezing means, removably attachable about the spike proximate to the aperture, for squeezing the flexible tube against the interior surface of the spike so as to regulate the flow of intravenous fluid.

Abstract: A system and method is provided for detecting the presence of drops in a fluid drop path, such as that in a medical infusion system, and for discriminating between signals resulting from true drops and signals resulting from aberrant fluid flow. A transducer generates a drop signal related to the presence of a drop in a fluid drop path. Also generated is a reference quantity related to the value of the drop signal in the absence of a drop. The deviation of the drop signal from the reference quantity is calculated, and is compared with first and second threshold values. The results of these two comparisons are then used to determined the presence or absence of a true drop.

Abstract: In a fluid flow control system a weight comparator compares the weight of fluid in a reservoir with a weight reference that is programmed to decrease at a desired rate. A fluid flow comparator compares the actual fluid flow rate with a programmed fluid flow rate and operates directly on a flow controller to control fluid flow in the system. The weight comparator operates indirectly on the flow controller by recurringly updating the programmed fluid flow rate so that flow is controlled on a current basis by the fluid flow comparator and on a long-term basis by the weight comparator.

Abstract: A dispensing arrangement in a fluid line that isolates a region of fluid in the line from pressure effects in the line outside the region. A housing of measuring fluid surrounds the region so that changes in the measurement fluid pressure cause changes in the pressure of the original fluid in the region. Predetermined volume increments of the measurement fluid are displaced, causing changes in the original fluid pressure in the region which are measured by a pressure transducer. The dispensing arrangement also repetitively dispenses fluid into and out of the region in increments monitored by the pressure transducer.

Abstract: An infusion pump has a removable reservoir including a piston and drive member. The drive member is an internally threaded elongated portion of the piston. A motor rotates a short drive screw, which engages the threads of the drive member to displace the piston in the reservoir. In one embodiment the piston is attached to the drive member by a severable central stem which breaks away to allow engagement with the drive screw. With the stem severed, the piston cannot be retracted, or the reservoir refilled. Other safety features are shown for locking the displaced piston in the reservoir. A digital metering system has a safety circuit to prevent dangerous failure modes of the rotation sensor and motor drive systems.